This invention relates generally to methods and tools for building construction. It relates more particularly to a method and tool for removing modular concrete forms from underlying rigid concrete.
Certain building sections such as foundations for buildings or bridges are typically constructed with concrete for its advantages of high compressive strength, resistance to degradation by ground and water contact, and lower total cost as compared to stacked masonry units. These concrete building sections are usually framed by concrete forms that create a mold into which fluid concrete is poured and cures. Concrete forms may be of any rigid material that will withstand the pressures of poured concrete. Historically, concrete forms were typically made from plywood with a thickness of at least one-inch, custom cut for a particular job site. These plywood forms were then strengthened with various vertical and horizontal bracing as appropriate for the project at hand.
Recent changes in the industry have led to the use of pre-fabricated modular forms or panels in standard sizes, where the modular forms are intended to be reused over numerous and varied projects. Modular concrete forms of the type described herein are known in the art. These modular forms fit together easily and reduce the need for customized forms; thereby reducing the labor involved in arranging them to receive poured concrete. Modular concrete forms typically include knobs that protrude from the side opposite that confining the concrete. These knobs allow bracing to be readily secured to bind adjacent forms to each other and to strengthen them against separation or rupture from the weight of concrete poured behind them.
After the concrete is cured sufficiently, usually a few days, the forms are removed. Whether custom made or prefabricated modular forms, the surface of the forms against which concrete comes in contact are pre-treated with a release agent, typically a diesel fuel based fluid, to facilitate removal without destroying the forms. Workers generally force prybars, wedges or the like between the concrete form and the hardened concrete to break the bond between them. Some workers use a hooked end of the prybar to xe2x80x98ratchetxe2x80x99 the edge of a modular form away from the concrete structure. Using the prybar in this way tends to deform the edge or a surface of the modular form that hinders future use of the form. This is because the prybar""s force is applied over a very limited surface area, whereas modular forms are engineered to withstand the forces of concrete applied broadly an entire surface. Other workers use a sledge to drive a wedge or the straighter end of a prybar between the modular form and the concrete to separate them. Both methods are used in the field and neither significantly reduces the strenuous labor of removing concrete forms from underlying rigid concrete. Neither method eliminates the need to forcibly insert a prybar tip between the modular form and the concrete to which it adheres, which is the most strenuous task in form stripping. Despite the release agent, many forms are bent, breached, or otherwise deformed during removal. This is a more significant concern with prefabricated modular concrete forms since their increased cost is often recouped only through repeated use.
What is needed in the art is a method and tool to minimize or overcome some of the above deficiencies. Based on the foregoing, it is an object of the present invention to provide such a method and tool for removing modular concrete forms from underlying concrete.
The present invention contemplates a method, a combination or apparatus, and a tool. The method of the present invention for removing modular concrete forms from rigid concrete comprises five distinct steps. First, provide a modular concrete form removal tool, wherein the tool itself comprising a claw end defining a notch particularly adapted to engage a knob protruding from the modular concrete form, a lever arm with an opposing end, and a fulcrum therebetween. Second, engage the claw end with the protruding knob. Third, place the fulcrum against an adjacent surface, such as the hardened concrete itself or an adjacent modular concrete form. Fourth, apply a force to the lever arm in the direction of the concrete so that the form will tend to separate from the hardened concrete. And repeating the process as necessary to remove additional modular forms.
The combination apparatus of the present invention comprises at least two modular concrete forms and a tool for removing a form from the concrete structure. More particularly, the modular concrete form comprises an interior surface to abut fluid concrete that is poured into the adjacent space. The form has an opposing second or exterior surface spaced from the interior surface, and knobs that project from the exterior surface. The tool of the apparatus comprises a claw end terminating in a tip and defining a notch particularly adapted to engage the knob, and a lever arm defining an end opposite the tip. The tool further includes a fulcrum between the claw end and the lever arm. This fulcrum forms an abutment surface that is disposed opposite a line between the tip and the end.
The tool of the present invention for removing modular concrete forms from hardened concrete comprises three main components: a claw end, a lever arm, and a fulcrum. The claw end terminates in a tip and has a notch particularly adapted to engage a knob protruding from the modular concrete form. The lever arm defines an end opposite the tip. The fulcrum is located between the claw end and the lever arm, and defines an abutment surface that is disposed opposite a line between the tip and the end. The abutment surface is spaced from the line by at least twice the thickness of the modular concrete form, and the fulcrum is attached to the remainder of the tool at a distance from the tip that is at least six times the thickness of the modular concrete form. The thickness of the modular concrete form is the distance between the form""s interior and exterior surfaces.